Potassium Fluoride → 1-(5,6,7,8-Tetrahydroimidazo[1,2-a]pyridin-3-yl)ethanone

Temperature

120 °C

142 mg of the 3-bromo-5,6,7,8-tetrahydroimidazo[1,2-a]pyridine [44-2] was dissolved in 2.5 mL of toluene, 81.6 mg of tetrakis triphenylphosphine palladium (0) and 477 μL of tributyl(1-ethoxyvinyl)tin were added, and the mixture was stirred overnight at 120° C. The reaction mixture was cooled back to room temperature to add 10% aqueous solution of potassium fluoride, and extracted with ethyl acetate. The organic layer was washed with 10% aqueous solution of potassium fluoride and with saturated brine in the subsequent order, and then was dried over anhydrous sodium sulfate. The insolubles were filtered, the filtrate was concentrated under reduced pressure, and then the purification by silica gel column chromatography was carried out. The obtained compound was dissolved in 2 mL of chloroform, 200 μL of 10% hydrochloric acid-methanol solution was added, and the mixture was stirred for 40 minutes. The liquid was basified by adding a saturated aqueous solution of sodium hydrogen carbonate, and was extracted with chloroform. The organic layer was washed with saturated brine, and then dried over anhydrous sodium sulfate. The insolubles were filtered, the filtrate was concentrated under reduced pressure, and the obtained residue was purified by preparative thin-layer chromatography to obtain 62.2 mg of 1-(5,6,7,8-tetrahydroimidazo[1,2-a]pyridin-3-yl)ethanone [44-3] as a pale yellow oily product.

1. temperatureThe reaction mixture was cooled back to room temperature
2. extractionextracted with ethyl acetate
3. washThe organic layer was washed with 10% aqueous solution of potassium fluoride and with saturated brine in the subsequent order
4. dry with materialwas dried over anhydrous sodium sulfate
5. filtrationThe insolubles were filtered
6. concentrationthe filtrate was concentrated under reduced pressure
7. customthe purification by silica gel column chromatography
8. dissolutionThe obtained compound was dissolved in 2 mL of chloroform
9. addition200 μL of 10% hydrochloric acid-methanol solution was added
10. stirringthe mixture was stirred for 40 minutes
11. additionby adding a saturated aqueous solution of sodium hydrogen carbonate
12. extractionwas extracted with chloroform
13. washThe organic layer was washed with saturated brine
14. dry with materialdried over anhydrous sodium sulfate
15. filtrationThe insolubles were filtered
16. concentrationthe filtrate was concentrated under reduced pressure
17. customthe obtained residue was purified by preparative thin-layer chromatography

ORD record

ord-418da12252c04ef5841298e232ebcf1c

Source dataset

uspto-grants-2010_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07718801B2